The present invention relates to a separate for separating particles from a fluid.
In many marine craft, a propeller at the end of a drive shaft extends away from the craft""s stem by out rigging via a bearing. The bearing is usually cooled and lubricated by water flowing through channels or grooves which extend through the bearing. When the marine vessel passes through water where sand or grit has been disturbed, the sand/grit particles can find their way into the lubricating grooves of the bearing. These particles are highly abrasive to the bearing, and result in the bearing quickly becoming worn.
There is therefore a need to minimise the amount of sand or other abrasive particles from entering the lubricating grooves of the bearing.
An object of the present invention is to provide a separator for separating particles entrained in a fluid.
In accordance with a first aspect of the present invention there is provided a separator for separating particles entrained in a fluid, said separator including:
a sleeve adapted to be mounted over a rotatable shaft for forming a cavity therebetween;
an inlet to the cavity;
an outlet to the cavity opposite the inlet; and
means for imparting a centrifugal force on fluid within the cavity, said means operatively connected to the shaft so that, in use, spinning of the shaft creates the centrifugal force,
wherein, in use, a slurry of fluid and particles enters of the cavity through the inlet, the particles are caused to separate from the fluid by action of the centrifugal force, the separated particles and fluid leave the cavity via the outlet with the particles tending to be closer to the sleeve than the shaft.
Preferably, the cavity increases in cross-sectional area along its length from the length towards the outlet.
In a first embodiment, the sleeve is frustoconical in shape with the narrow end of the cone at the inlet and the wide end at the outlet, whereby the size of the cavity increases along its length from the inlet to the outlet, which causes the movement of the slurry through the cavity to slow the further it progresses along the length of the separator, thereby increasing the centrifugal action on the fluid as it moves along the length of the separator.
In the first embodiment, the means for imparting a centrifugal force is in the form of one or more paddles projecting from the shaft into the cavity, the paddles causing the fluid to rotate about the longitudinal axis of the shaft as the shaft spins.
In a second embodiment, the cavity is of a helical shape. The helix shaped cavity, acting as said means so that as it is rotated, the centrifugal force is imparted on the fluid in the cavity. Preferably, the helical shape assists in moving fluid through the cavity from the inlet to the outlet. More preferably, there is a plurality of helical shaped cavities. Preferably, there is provided a first raceway between the inlet and the helical cavities.
Preferably, the inlet is of a smaller area than the outlet and thereby limiting the amount of fluid that enters the cavity.
Preferably, the outlet includes a parting means arranged to portion an inner layer of fluid substantially devoid of the particles from an outer layer of the fluid carrying the particles. More preferably, the parting means is in the form of a blade closely encircling the shaft. Preferably, the outlet includes a chamber at the outlet end of the cavity between the sleeve and the shaft, the chamber arranged to receive a parting means for portioning an inner layer of fluid substantially devoid of the particles from an outer layer of fluid carrying the particles.
Preferably, the sleeve is arranged to rotate about its axis relative to the parting means.
Preferably, the outer layer is ejected from a first exist of the outlet. Preferably, the parting means includes a turbulence means for slowing the exit of the fluid carrying the particles from the outlet.
Preferably, the parting means is arranged to be fixed to a bearing.
Preferably, the parting means includes a scoop means for scooping the inner layer of fluid away from the blade to a second exit of the outlet.
Preferably, the scoop means is in the form of a plurality of curved channels. Preferably, the scoop means is provided with a second raceway between the curved channels and the second exit.
According to a second aspect of the present invention, there is provided a separator and parting means combination, the separating means as defined above and the parting means is arranged to partition an inner layer of fluid substantially devoid at particles from an outer layer of fluid carrying the particles.
According to a third aspect of the present invention, there is provided a separator, parting means and a bearing combination, the separator and parting means as defined above, the bearing arranged to receive the inner layer of fluid from the parting means.